1 Features

• Meets or exceeds the requirements of the TIA/

EIA-485A and TIA/EIA-232F standards

• 3 transmitters, 5 receivers for RS-232

• 1 transmitter, 1 receiver for RS-485

• On-chip switchable 120Ω termination resistor for

RS-485 mode

• Integrated charge-pump for RS-232 signaling

• 3V to 5.5V supply voltage

• 1.65V to 5.5V supply for logic data and control

signals

• RS-485 differential output exceeds 2.1V for

PROFIBUS compatibility with 5V supply

• Large output swing (typical ± 9V) for RS-232 mode

• SLR Pin Selectable Data Rates:

– RS-232 3T5R mode: 250kbps and 1Mbps

– RS-485 half-duplex and full-duplex mode:

500kbps and 20Mbps

• Bus I/O protection

– ±16kV HBM ESD

– ±8kV IEC 61000-4-2 contact and ±15kV air-gap

discharge

– ±4kV IEC 61000-4-4 fast transient burst

• Diagnostic loopback for both RS-232 and RS-485

modes

• Pin-selectable diagnostic loopback

• Shutdown pin for low current consumption (10μA

typical) in disabled state

• Glitch-free power-up/down for hot plug-in capability

• 1/8 unit load (up to 256 bus nodes) for RS-485

• Open, short, and idle bus failsafe for RS-485

receiver

• Bus short-circuit protection, thermal shutdown

• Extended ambient temperature range: -40°C to

125°C

• Space-saving thermally efficient 6mm x 6mm

VQFN-40 package

• Pin compatible with industry standard

2 Applications

• Industrial PC

• Factory automation and control

• HVAC systems

• Building automation

• Point-of-sale terminals

• Grid infrastructure

• Industrial Transport

3 Description

THVD4431A is a highly integrated and robust

Multiprotocol transceiver supporting RS-232, RS-422

and RS-485 physical layers. The device has three

transmitters and five receivers to enable 3T5R

RS-232 port. The device also integrates one

transmitter and one receiver to enable half and full

duplex RS-485 port. MODE selection pins enable

shared bus and logic pins for the protocols to share

a common single connector. Integrated termination for

RS-485 bus pins and for RS-232 receiver inputs need

no external components to realize a fully-functional

communication port. The device has a slew rate

select feature that enables the device for use at two

maximum speeds based on the SLR pin setting.

The device features integrated Level 4 IEC ESD

protection, eliminating the need for external systemlevel

protection components. Diagnostic loopback

mode for both RS-232 and RS-485 is provided to

check for logic to bus and bus to logic path functional

integrity and check for cable and connector shorts. In

addition, the RS-485 receiver fail-safe feature drives

logic high on received logic output when the bus

inputs are open or shorted together or when the bus

is idle. Shutdown mode consumes ultra-low current

(10μA typical), which is good for power-sensitive

applications. The device needs 3 to 5.5V supply that

powers the charge pump for RS-232 and the drivers

or receivers for both RS-232 and RS-485. A separate

logic supply VIO (1.65V to 5.5V) enables interface with

low level microcontrollers.